should I buy an existing Allstate agency?

I have been selling commercial insurance for 10 years and have been very successful. There's an opportunity in my home town to purchase a well established Allstate book. The owner is well respected and the book has a high retention. He is at retirement age and is willing to work with me through the initial start up. I have met with the Regional rep and passed all the tests.
Should I run or take a shot? What factors should I consider besides the obvious?